The invention relates to the removal of inorganic salts from an unpotable water stream containing such salts, and specifically to the formation of a potable water stream with minimal waste liquid stream discharge.
The conversion of inorganic salt-containing inland water streams to potable water generally includes the concentration of the dissolved solids into one fraction while reducing the remaining fraction to potable specifications, e.g., by reverse osmosis, electrodialysis, and/or ion exchange. These procedures require that the concentrated brine be discharged as a waste liquid stream. This is particularly unsatisfactory in the treatment of inland waters far removed from a sea coast, as there is no convenient mode of disposal of the concentrated liquid streams. It would be desirable to provide a process in which liquid wastes produced in such a conversion are reduced to very low levels, while conversely increasing the potable product water yield of untreated feed water.